如何 grep 和执行命令(对于每个匹配项) [英] How to grep and execute a command (for every match)

问题描述

如何在一个文件中 grep 并为每个匹配执行一个命令?

How to grep in one file and execute for every match a command?

文件:

foo
bar
42
foo
bar

我想为 foo 上的每个匹配执行例如 date.

I want to execute to execute for example date for every match on foo.

以下尝试不起作用:

grep file foo | date %s.%N

怎么做?

推荐答案

grep file foo | while read line ; do echo "$line" | date %s.%N ; done

在脚本中更易读:

grep file foo | while read line
do
    echo "$line" | date %s.%N
done

对于每一行输入，read会将值放入变量$line中，while语句会执行循环体do 和 done 之间.由于该值现在位于变量中而不是标准输入中，因此我使用 echo 将其推回标准输入，但您可以只执行 date %s.%N "$line"，假设 date 是这样工作的.

For each line of input, read will put the value into the variable $line, and the while statement will execute the loop body between do and done. Since the value is now in a variable and not stdin, I've used echo to push it back into stdin, but you could just do date %s.%N "$line", assuming date works that way.

避免在`grep file foo`中使用for line，这很相似，因为for总是在空格处中断，这成为读取文件列表的噩梦:>

Avoid using for line in `grep file foo` which is similar, because for always breaks on spaces and this becomes a nightmare for reading lists of files:

 find . -iname "*blah*.dat" | while read filename; do ....

使用 for 会失败.

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